A cyst is an abnormal fluid-filled sac that can form in many parts of the body, such as the kidney, liver, pancreas, spleen and heart. Polycystic disease is a disease that occurs when a large number of cysts cause damage to these organs. For example, polycystic kidney disease (PKD) is a disease characterized by the growth of numerous cysts throughout the kidneys. The PKD cysts can slowly replace much of the mass of the kidneys, reducing kidney function and leading to kidney failure. About half the people with the most common form of PKD progress to kidney failure and require dialysis or kidney transplantation. PKD can also cause cysts in other organs, most commonly the liver, but also the spleen, pancreas, heart and blood vessels in the brain. About 500,000 people have PKD in this country, and PKD is the fourth leading cause of kidney failure. Autosomal dominant PKD (ADPKD) accounts for about 90% of all PKD cases and about 8-10% of all cases of end stage renal disease. Currently, there is no approved treatment or cure for PKD. Present medical and surgical procedures only reduce the pain resulting from expansion of renal cysts or resolve other symptoms associated with PKD such as infections or high blood pressure. None of these procedures, aside from kidney transplantation, appreciably slows the progression of the disease.
Thus, there is a need for agents and methods for preventing the onset of, or slowing the progression of PKD.